As the micro computer industry advances, present mobile terminal devices (such as tablet PCs, PDAs and mobile phones) are designed with an increasingly smaller volume and increasingly more functions (such as the camera, calendar and game functions). Particularly, various mobile terminal devices allow users to browse and use information on networks via wireless connection, since related communication technologies are developed rapidly.
Most of the present mobile terminal devices use at least one network protocol (such as WiFi), but if the number of access points corresponding to the network protocol in some regional districts is too small, then users in these districts will be unable to log on a network through the mobile terminal device, and the convenient networking will be affected adversely. Although some manufacturers have designed various mobile terminal devices for different network protocols, yet the conventional mobile terminal devices still have existing problems. Firstly, not every user requires so many network protocols, and thus manufacturers have to design a mobile terminal device used for one particular network protocol and a mobile terminal device used for several different network protocols. For different circuit designs and productions, the production and design costs will be increased. Secondly, the mobile terminal devices with different network protocols generally come with a more complicated design of the internal circuits and the installation position of an antenna and require more components, which are unfavorable for the light, thin, short and compact design. The conventional mobile terminal devices not only require a higher level of difficulty on the circuit design, but also fail to meet user requirements. Thirdly, the mobile terminal devices with several network protocols are usually more expensive, and the higher selling price will cause a lower consumer's purchase intention and make it more difficult for manufacturers to cover their cost. Therefore, related manufacturers overcome the aforementioned problem by designing a leather cover sheathable to the mobile terminal device, wherein the mobile terminal device can be connected to networks of several different network protocols through the leather cover. To clearly disclose the aforementioned technical content, the mobile terminal device such as the WiFi IPod touch manufactured by Apple Inc. and the leather cover applied to such mobile terminal devices are used as examples for illustrating the present invention as follows.
With reference to FIG. 1 for the aforementioned leather cover, the leather cover 1 includes a sheathing space 10 concavely formed on a side of the leather cover 1 and provided for receiving and accommodating a mobile terminal device 11, a battery 12, a printed circuit board 14, and a data interface 16 installed in the leather cover 1, wherein the battery 12 is electrically coupled to the printed circuit board 14 for transmitting current to the printed circuit board 14, and maintaining a normal operation of the printed circuit board 14. The printed circuit board 14 includes a subscriber identity module (SIM) slot 141 formed thereon and provided for inserting and connecting a SIM card 15 in order to read information from the SIM card 15. The printed circuit board 14 further includes a communication module 143 coupled to a communication network (such as GSM), and the data interface 16 can be inserted and connected to a port 111 of the mobile terminal device 11, such that the leather cover 1 and the mobile terminal device 11 can be electrically coupled to each other, and the mobile terminal device 11 can be connected to the communication network through the communication module 143. If users purchase the mobile terminal device 11 or the mobile terminal device 11 with the leather cover 1 according to their personal preference, manufacturers no longer require designing a mobile terminal device 11 with different network protocols, so as to reduce the design cost of the manufacturers significantly.
In FIG. 1, although the aforementioned leather cover 1 can be provided for connecting the mobile terminal device 11 to the communication network, yet its application still has many drawbacks. Firstly, the leather cover 1 is electrically coupled to the mobile terminal device 11 through the data interface 16, while the battery 12 and the SIM card 15 are assembled into the leather cover 1 and covered by the mobile terminal device 11. Therefore, if a user wants to change the battery 12 or the SIM card 15, the user has to plug and unplug the data interface 16, and the port 111 of the mobile terminal device 11 or the data interface 16 of the leather cover 1 may be damaged easily after a long time of use, and the user has to spend an additional maintenance fee or even has to buy a new one. Secondly, the leather cover 1 is electrically coupled to the mobile terminal device 11 through the data interface 16, such that one leather cover 1 can be used for a set of mobile terminal device 11. If the user needs not to use the mobile terminal device 11 currently, and others want to connect to a communication network through the leather cover 1, the mobile terminal device 11 disposed in the leather cover 1 must be removed first, and then another mobile terminal device 11 is inserted and connected. Obviously, such application is inconvenient to users who want to share the communication network of the leather cover 1. Finally, if the user wants to change to another different model of the mobile terminal device 11 and/or the model of the port 111 of the mobile terminal device 11, the leather cover 1 will be unable to electrically couple to the mobile terminal device 11 through the data interface 16, and the user has to buy another leather cover 1 in compliance with the model of the port 111. Obviously, the scope of applicability of the leather cover 1 is limited substantially.
Therefore, it is an important subject for related network manufacturers to design a feasible solution and develop a convenient product to overcome the aforementioned shortcomings of the prior art.